Sorry I avoided this post, as is a habit of mine with training posts. - sorry-
Ok here goes, (remember you asked for it), so this is likely to be long, get comfy.
First off, it isn't a super grand idea to correct or punish a dog for barking in ummmm about 95% of cases. If you're out for a walk and a dog and it barks and you correct or punish, you run an extremely high risk of teaching that dog that whatever he is barking out means something unpleasnant is on the way. This creates a couple of lovely problems in some dogs. Better to redirect the dog's focus and teach them that 1)that other dog isnt bad so just don't worry about him 2)hey look another dog, do I get a treat, toy, petted..... ?? He'll look to you for something and likely be happy about it, instead of expecting to be told NO and pulled in the other direction.
Everyone is different Pam, but I am not a huge fan of physical correction be it with your hand, or a leash. Thats the lazy way out and really doesn't teach the dog much. I would argue that fact with my last breath. Teaching through fear or pain is going to eventauly come back to bite you, maybe literaly.
I might try a completely different set of tactics wich will probably seems counter productive to you. Have you ever heard a trainer say that you should teach a dog to speak before you teach him to be quiet? It makes sense, teach Barking so you can teach no barking.
Jazz will bark at the fence, and out the window of the shop, and occasionaly on the table if somebody comes in. Obviously I don't mind a few barks, espeicaly if I am alone. I like the warning. I got a big dog for the big bark since I am home alone so often. I to needed a way to stop the behavior after I had been warned.
So, pick a word that is going to mean the end of barking. *rule - you aren't allowed to pick a word with NO in it* (sorry) I like words like Thankyou, enough, or anything else you can think of.
Have a leash and treats handy. If you use a marker like a clicker, whistle, or a verbal cue, which I would strongly suggest, have that ready too.
The next time she barks, use your word, and get her attention with a treat. Sanp a leash on her if you have to drag her away from the window
Mark the behavior (if you're using a marker) when she turns her attention from the window to you. You want her to think that everytime she needs to bark at something outside she should get something yummy inside (use dog food if you're worried about her getting fat). You may have to do a few obedience cues to keep her interested in you for a bit instead of wanting to go straight back to the window.
Now I know, it sounds like you are rewarding bad behavior, but the goal here is for her to bark at something outside, warning you it's there, and then come running over to you when you tell her that'll do.
Method two/ what to do next
If you aren't interested in the above training, you can also try time out. Use your stop barking cue, and if she doesn't don't say another word take her by the collar and without any fuss say time out and put her in her crate. Use no emotion in your voice when you say time out. This is NOT punishment, her crate is not a bad place. It's just, I need a break, you need a break, go here. Make sure she doesn't have anything fun in her crate like a bone or a toy. I fyou sent your kid to time out in his room and he had an xbox to entertain him would time out be effective? No. Same deal with the dog. Time outs are no more than 3 minutes (provided the dog isn't barking), and you when you let them out all if forgiven no hard feelings. Like hitting the reset button. You don't make a big deal about of letting them out though, no good girls or anything like that. Just let her out. If she goes right back to the window and starts barking she goes right back in time out for another 2 or 3 minutes.
You can also use time out after the initial reward if she won't stop going to the window and barking so both methods can be combined.
Keep this in mind though, that training away from this behavior is going to take a while. She's been allowed to continue for long enough to make it a habit and we know habits are hard to break. Aside from that, your previous efforts to stop her were ineffective and she's learned she doesn't HAVE to stop. So she is going to be twice as determined to bark out that window. The behavior may be worse before it gets better. Thats OK, thats how you know you're really getting through. It's a sign that they are making one last huge effort to hang onto the behavior thats worked for them for so long.